Process for dyeing human hair with diazo salts

ABSTRACT

Described is a process for dyeing keratin-containing material with developing dyes by applying, successively in any desired sequence or simultaneously, to the keratin-containing material to be dyed, diazo salts and coupling components, and coupling these together, which process is characterized in that there are used coupling components of the formula ##STR1## wherein R represents an unsubstituted or substituted aryl group.

The invention relates to a process for dyeing keratin-containingmaterial, particularly human hair, with developing dyes.

Dyes used hitherto for dyeing human hair are in particular oxidationdyes, e.g. those based on p-phenylenediamine and benzidine. These dyeshowever have many disadvantages. Attempts have therefore been made tofind for the dyeing of keratin-containing material, especially humanhair, a dyeing process which eliminates these disadvantages.

For dyeing human hair there is thus known a dyeing process usingdeveloping dyes which are formed from a diazo salt and a couplingcomponent, such as a benzene derivative or naphthol or1-phenyl-3-methyl-pyrazol-5-one. These coupling components, particularlyα- and β-naphthol, have however a low affinity for human hair andconsequently are not particularly well suited for the intended purpose.

It has now been found that with use of a coupling component of the2-hydroxy-naphthalene-3-carboxylic acid arylamide class it is possiblein a surprising manner to overcome the stated disadvantages andfurthermore to cover, with only one coupling component, the colour rangefrom red to black by variation of the diazo component.

The process according to the invention for dyeing keratin-containingmaterial with developing dyes by applying, successively in any desiredsequence or simultaneously, to the keratin-containing material to bedyed, diazo salts and coupling components, and coupling these together,is characterised in that there is used a coupling component of theformula ##STR2## wherein R represents an unsubstituted or substitutedaryl group.

As an aryl group, R represents for example a phenyl or naphthyl group(α- or β-). Substituents are for example: lower alkyl groups such as themethyl group; lower alkoxy groups such as the methoxy or ethoxy group;halogen such as, in particular, chlorine; the nitro group; the phenylgroup, which for its part can be further substituted by the substituentsmentioned. The aryl group R can however also be substituted by severalidentical or different substituents of the said kind. Furthermore, theradical R can be substituted by a further coupling component of theformula given above.

Examples of radicals denoted by the symbol "R" are given below: ##STR3##

The preferred coupling component is that wherein R represents anunsubstituted phenyl group.

These coupling components are known and can be produced by knownmethods.

As diazo components necessary as the second component for the synthesisof the developing dye it is possible to use the diazotised aromatic orheteroaromatic amines known from the chemistry of azo compounds,particularly monoamines, especially aminobenzenes. The commercialstabilised diazonium compounds are particularly suitable for the processaccording to the invention.

As examples of applicable diazo components are listed the following inthe form of the free amines:

2- or 3-chloroaniline, 2-, 3- or 4-nitroaniline, 2-methoxyaniline,2,5-dichloroaniline, 3,5-di-trifluoromethylaniline,2-chloro-5-trifluoromethylaniline, 2-methoxy-5-chloroaniline,2-methyl-3-chloroaniline, 2-methyl-5-chloroaniline,2-methyl-4-chloroaniline, 2-nitro-4-chloroaniline,2-trifluoromethyl-4-chloroaniline, 2-nitro-4-methylaniline,2-nitro-4-methoxyaniline, 2-nitro-4-ethoxyaniline,2-methyl-4-nitroaniline or 2-methyl-5-nitroaniline,2-methoxy-4-nitroaniline or 2-methoxy-5-nitroaniline,2-ethylsulphonyl-5-trifluoromethylaniline,3-ethylsulphonyl-6-methoxyaniline,3-N,N-diethylaminosulphonyl-6-methoxyaniline,3-N-n-butylaminosulphonyl-6-methoxyaniline,1,4-diamino-2,6-dichlorobenzene, 2,4-dimethyl-3-nitroaniline,2-methoxy-4-methyl-5-nitroaniline, 2-chloro-4-cyano-5-methylaniline,2,5-dimethoxy-4-cyanoaniline, 4-phenylaminoaniline,2-methoxy-4-phenylaminoaniline, 4-(4'-methoxyphenylamino)-aniline,4',4"-diamino-diphenylamine, 2-phenylsulphonylaniline,2,5-dimethoxy-4-phenylcarbonylamino-aniline,2,5-diethoxy-4-phenylcarbonylamino-aniline,2-(4'-chlorophenoxycarbonyl)-aniline,3-benzylsulphonyl-6-methoxy-aniline,2,5-dimethoxy-4-(4'-methylphenoxyacetylamino)-aniline,2,5-diethoxy-4-(4'- or 2'-methylphenoxyacetylamino)-aniline,2-phenoxy-5-chloroaniline, 2-(4'-chlorophenoxy)-5-chloroaniline,4-aminoazobenzene, 3-methoxy-4-aminoazobenzene, 2',3- or2,3'-dimethyl-4-aminoazobenzene,2,5-dimethoxy-4'-nitro-4-aminoazobenzene,2-methyl-5-methoxy-4,4'-diaminoazobenzene,2-ethyl-5-methoxy-4-amino-4'-chloroazobenzene,2-methyl-5-methoxy-4-amino-2'-nitro-4'-methylazobenzene,2-amino-4-methoxy-5-methyl-2'-chloro-4'-nitroazobenzene,2,5-dimethoxy-4-amino-2'-N,N-dimethylaminocarbonyl-4'-nitroazobenzene,2,5-dimethoxy-4-amino-2',6'-dichloro-4'-nitroazobenzene,2-chloro-4-benzoylamino-5-methoxyaniline,2,4-dimethyl-5-benzoylaminoaniline,2-N,N-diethylaminosulphonyl-4-benzoylamino-5-methoxyaniline,2-methoxy-4-benzoylamino-5-methylaniline,2,5-dimethoxy-4-benzoylaminoaniline, 2,5-diethoxy-4-benzoylaminoaniline,4-(1'-naphthylazo)-aniline, 1-(2'-ethoxyphenylazo)-4-aminonaphthalene,2-methyl-4-amino-5-ethoxy-4'-(4"-aminophenylamino)azobenzene, 1- or2-aminonaphthalene, 3-benzoylamino-4-methoxyaniline and1-aminoanthraquinone.

Preferred diazo components are aminobenzenes which are mono- orpolysubstituted by halogen, particularly chlorine; lower alkyl,especially methyl; lower alkoxy, particularly methoxy or ethoxy;benzoylamino; alkoxyphenylamino, especially methoxyphenylamino;phenylamino; or by the phenylazo group, and this phenyl group is furthersubstituted by the nitro group and/or lower alkyl, such as methyl.

Before diazotisation, these amines are converted into their salts, forexample into the hydrochlorides or hydrosulphates, if necessary byheating, with moderately concentrated acid. The subsequent diazotisationcan be performed by customary methods, e.g. by means of sodium nitriteand mineral acid, such as hydrochloric acid. Instead of using diazotisedamines, it is also possible to use dye salts, i.e. stabilised diazoniumcompounds. Suitable stabilisers and separating reagents for the dyesalts are: metal chlorides such as ZnCl₂, CdCl₂, CoCl₂ or MnCl₂, whichcan be separated with the diazo compound as a complex from the aqueoussolution, aromatic sulphonic acids which can be used as free acids or asalkali salts, and which form with diazonium compounds true salts,especially naphthalene-disulphonic acids, hydrofluoboric acid, whichlikewise forms with diazo compounds true salts, andacylaminoaryl-sulphonic acids, such as acetylsulphanilic acid. In somecases, also the diazonium chlorides or acid sulphates themselves can beseparated and used. The stabilised diazonium salts or diazoamino saltscontain also inert salts. With the use of dye salts, an addition ofalkali-binding agents, such as acetic acid, formic acid, sodiumacetate/acetic acid, chromium acetate or mono- or disodium phosphate, isin some cases necessary, since dye salts are broken down by alkaliaction.

The application of the diazo and coupling components to thekeratin-containing material, particularly to human hair, is effectedpreferably in two stages, in such a manner that firstly one of the twocomponents of the developing dye, preferably the coupling component, isapplied to the material, and is subsequently coupled on the materialwith the diazo component. It is however also possible to apply thecoupling component and diazo component simultaneously to the hair. Inthis respect, the conditions under which the process is performed dependon the nature of the keratin-containing material to be dyed. Thecoupling itself occurs in the alkaline pH range of about 7 to 12,preferably up to pH 11.

If living material is involved, that is, human or animal hair, thecoupling and diazo components are applied at about 15° to 40° C.,preferably at room temperature, e.g. by spraying or by applying in theform of an aqueous solution, nonionic cream, emulsion or gel. Thereaction time in the case of the component first applied is about 1 to25, preferably 2 to 10, minutes. The material is then optionally rinsedand intermediately dried or, conversely, firstly intermediately driedand then rinsed; and the second component is subsequently applied,preferably in the same manner. The time required for the couplingreaction is about 0.5 to 20 minutes, preferably 1 to 10 minutes. Thedyed keratin-containing material, e.g. human hair, is afterwards rinsed,optionally with the addition of preferably nonionic surface-activeagents, and subsequently dried.

Dead material, such as skins, furs, feathers, or wigs made from humanhair, are impregnated with solutions of the coupling or diazo componentspreferably by immersion in these solutions. The temperature for this canbe, e.g., up to 60° C. After impregnation with the first component, thekeratin-containing material can be optionally squeezed out orcentrifuged before it is impregnated with the second component necessaryfor the formation of the dye.

An aqueous solution of the coupling component is preferably prepared byadding the coupling component to water, optionally together with asolubility-promoting agent, such as alcohol, and adding alkali, e.g.ammonia or aqueous sodium hydroxide solution, until a clear solution isobtained. The diazo components, which are preferably used as stabiliseddiazonium salts, are employed as aqueous solutions.

Coupling and diazo components are preferably used in approximately equalmolar amounts. An excess of up to about 100% of one component,preferably the diazo component, is not harmful: indeed it frequentlyleads to good results.

In the process according to the invention, the coupling and diazocomponents can be used as homogeneous substances. Since however in thedyeing of keratin-containing material, particularly human hair, mixedshades are often desired, it is also possible to use mixtures of thecoupling components and/or of the diazo components.

The concentration of the solutions is generally between 0.1 and 10%,preferably between 0.5 and 5%, of coupling or diazo component, relativeto the total composition.

For producing creams, emulsions or gels, the solutions of the couplingand diazo components, respectively, are provided with the customaryadditives, such as surface-active agents, preferably of a nonionicnature, such as fatty acid ethanolamides, polyalcohols (ethylene oxidepolymers with a degree of polymerisation of 200 to 1000) or additionproducts of ethylene oxide with fatty acids, with fatty alcohols, withfatty amines or with alkylphenols. And also anion-active compounds canbe added, such as alkylsulphonates, alkylbenzenesulphonates and fattyalcohol sulphates. Creams of this kind, particularly those with thecoupling component, are storage-stable at a temperature of about -10° C.to +45° C. for about 2 months.

Furthermore, the solutions, creams, emulsions or gels can containfurther additives, for example thickening agents such as starch ormethylcellulose, Vaseline®, higher fatty alcohols, paraffin oils, fattyacids, as well as perfume oil or hair tonics, such as pantothenic acidor cholesterol. These additives are used in the customary amounts.

A preferred method of application of the coupling and diazo componentsto human hair consists of pre-shampooing the hair with the couplingcomponent in shampoo form, especially with a cream-like shampoo, and,without intermediate rinsing, after-shampooing with the diazo component,likewise in shampoo form; or alternatively applying both components incream form.

The process according to the invention is suitable in particular forshading or dyeing; it can however be used also for overdyeing,especially for overdyeing human hair.

There are obtained by this process deeply coloured dyeings having goodproperties in service. By properties in service are meant, e.g.:fastness to washing, the possibility of turning dyed hair blonde(oxidise with H₂ O₂), fastness to cold setting, fastness to rubbing,fastness to light, absorption of the components in the case of damagedhair, fastness to perspiration and behaviour with regard to permanentwaving.

The process according to the invention can be carried out both onuntreated keratin-containing material, particularly on human hair, andon treated hair, such as on bleached or permanently-waved hair.

The azo dyes developed on the keratin-containing material are known orcan be produced by methods known per se.

It is possible by the process according to the invention to produce withonly one coupling component shades from red to black with variation ofthe diazo component. The process of the invention moreover avoids theuse of oxidation dyes, and can be performed at room temperature. Theprocess according to the invention is furthermore distinguished by theease with which it can be carried out, and by the fact that a chemicallydefinable dye is formed, whereas with oxidation dyes there are obtainedobscure indefinable mixtures of completely to only partially oxidisedamines, mixed with intermediate products.

The following Examples serve to illustrate the invention. Percentagesare percent by weight, parts are parts by weight and temperatures are indegrees Centigrade. The diazo components (amines) used were employed asstabilised stabilized diazonium compounds in commercial form.

EXAMPLES 1-18

There is prepared a 1% aqueous solution of the coupling component of theformula ##STR4## by introducing this into distilled water, anddissolving it by the addition of 2% ethanol and 1% sodium hydroxidesolution.

A bundle of grey human hair weighing 0.3 g is immersed in 50 ml of thissolution, and is left for 15 minutes at room temperature in thissolution (pH value about 11).

The bundle of hair is subsequently removed from the solution; the bundleis squeezed out briefly with a glass rod, and is then immersed for 5minutes at room temperature in a 1% aqueous solution of one of thestabilized diazonium compounds listed in the following Table; it issubsequently rinsed under running water and dried in air.

Dyed hair which displays the respective shade given in column III of theTable and which has good properties in service is obtained.

                                      Table                                       __________________________________________________________________________    I  II                              III                                           Stabilized diazonium compounds  Shade on                                   Ex.                                                                              in the form of the free amine   human hair                                 __________________________________________________________________________     1                                                                                ##STR5##                       scarlet                                     2                                                                                ##STR6##                       reddish- black                              3                                                                                ##STR7##                       black                                       4                                                                                ##STR8##                       red                                         5                                                                                ##STR9##                       carmine red                                 6                                                                                ##STR10##                      blackish- blue                              7                                                                                ##STR11##                       dark blue                                  8                                                                                ##STR12##                      bluish- black                               9                                                                                ##STR13##                      currant shade                              10                                                                                ##STR14##                      black                                      11                                                                                ##STR15##                      black                                      12                                                                                ##STR16##                      red                                        13                                                                                ##STR17##                      scarlet                                    14                                                                                ##STR18##                      brown                                      15                                                                                ##STR19##                      reddish-brown                              16 stabilized diazonium compound from Example 1                                  +                               brown                                         stabilized diazonium compound from Example 7                                  (1:1)                                                                      17 stabilized diazonium compound from Example 5                                  +                               brown                                         stabilized diazonium compound from Example 8                                  (1:1)                                                                      18 stabilized diazonium compound from Example 6                                  +                               black                                         stabilized diazonium compound from Example 10                                 (1:1)                                                                      __________________________________________________________________________

EXAMPLE 19

A cream emulsion is prepared by adding 1 part of the coupling componentof the formula ##STR20## to 75 parts of water, dissolving it by theaddition of ammonia, subsequently adding 10 parts of fatty alcoholsulphate (sodium salt, chain length C₁₂ -C₁₈) as well as 10 parts offatty alcohol (chain length C₁₂ -C₁₈), and making up to 100 parts withwater.

This cream emulsion is applied at room temperature to a bundle of greyhuman hair by rubbing in, and leaving it to react for 15 minutes. Thehair is rinsed briefly with water, and there is then applied, by rubbingin, an emulsion which has been obtained by working 1 part of the amineof the formula ##STR21## in the form of a stabilized diazonium compound,as well as 10 parts of the above-used fatty alcohol and fatty alcoholsulphate, into 79 parts of water.

A reaction time of 5 minutes is allowed; the hair is then thoroughlyrinsed, with the addition of a customary washing agent, to obtain hairwhich is dyed violet and which has good properties in service.

EXAMPLE 20

A bundle of bleached strands of hair is dyed as follows: The couplingcomponent of the formula ##STR22## is applied, in a nonionic cream formcontaining 2 percent by weight of coupling component, at 27° and at a pHvalue of 9.5 for 10 minutes to the strands of hair. The excess cream isthen removed as far as possible by wiping off, and the strands of hairpretreated in this manner are intermediately dried. After intermediatedrying, the diazo component, produced from the amine of the formula##STR23## is applied as an aqueous solution containing 2% of diazocomponent, at the same temperature but with a shorter reaction time. Thehair is then washed and dried.

Hair which is dyed bluish-black and which has good fastness propertiesin service is obtained.

EXAMPLE 21

10 g of a chrome tanned sheepskin, shorn to about 15 mm, is wetted backfor one hour, in a dyeing drum, at 40° in 200 ml of an aqueous solutioncontaining 0.2 g of anhydrous sodium carbonate, 0.2 g of 24% ammonia and0.1 g of a nonionic detergent; the material is subsequently rinsed andcentrifuged. This material is introduced into 200 ml of a liquor at 25°,obtained by dissolving 0.1 g of the coupling component of the formula##STR24## and 0.05 g of sodium carbonate with the subsequent addition of0.1 ml of an 85% aqueous formic acid, and is treated for 30 minutes atthis temperature in a dyeing drum. The material is afterwards rinsed andcentrifuged. The sheepskin is then immersed in 200 ml of a liquid at25°, which contains 0.4 g of the diazo component produced from the amineof the formula ##STR25## and 0.1 g of a nonionic detergent, and treatedfor 30 minutes at 25°; it is subsequently rinsed, centrifuged and dried.

A sheepskin dyed in a scarlet shade is obtained.

EXAMPLES 22-27

If the process is carried out as described in Example 1 except thatinstead of the coupling component used therein the same amount of thecoupling components given in the following Table in column II is used,there is obtained dyed hair which has the respective shade shown incolumn III and which has good properties in service.

    __________________________________________________________________________                                                 Shade on                         Ex.                                                                              Coupling component                        human hair                       __________________________________________________________________________    22                                                                                ##STR26##                                scarlet                          23                                                                                ##STR27##                                "                                24                                                                                ##STR28##                                "                                25                                                                                ##STR29##                                "                                26                                                                                ##STR30##                                "                                27                                                                                ##STR31##                                red                              __________________________________________________________________________

We claim:
 1. A process for dyeing human hair with developing dyes whichcomprises applying to said hair, at temperatures of from about 15° to40° C., an effective amount for dyeing of aqueous solutions of diazosalts and coupling components successively in any desired sequence, orsimultaneously, and coupling said diazo salts and coupling componentswith each other, wherein the coupling component is a2-hydroxy-naphthalene-3-carboxylic acid amide of the formula ##STR32##wherein R represents a member selected from the group consisting of anunsubstituted aryl group and a substituted aryl group.
 2. The process ofclaim 1 wherein R represents a member selected from the group consistingof(1) phenyl, (2) α-naphthyl, (3) β-naphthyl, (4) components (1), (2),or (3) substituted with substituents selected from the group consistingof lower alkyl groups, lower alkoxy groups, halogens, nitro groups andmixtures thereof, (5) components (1), (2) or (3) substituted withphenyl, (6) components (1), (2) or (3) substituted with phenylcontaining substituents selected from the group consisting of loweralkyl groups, lower alkoxy groups, halogens, nitro groups and mixturesthereof, and (7) biphenyl having the formula ##STR33##
 3. Processaccording to claim 2, wherein R represents phenyl.
 4. Process accordingto claim 1, wherein the diazo salts used are stabilised diazoniumcompounds of monoamines.
 5. Process according to claim 4, wherein thediazo salts used are stabilised diazonium compounds of aminobenzenederivatives.
 6. Process according to claim 5, wherein the aminobenzenederivatives used are aminobenzenes which are mono- or poly-substitutedby halogen; lower alkyl; lower alkoxy; benzoylamino; alkoxyphenylamino;phenylamino; or by the phenylazo group, and this phenyl group is furthersubstituted by the nitro group or lower alkyl.
 7. Process according toclaim 1 wherein there is firstly applied the coupling component andsubsequently the diazo salt to the human hair to be dyed.